<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>半透明效果</title>
<style type="text/css">
ul {
	list-style:none;
	margin:10px;
	padding:0;
	background:url(../images/charactor.png);
	height:160px;
}
li {
	float:left;
	margin:5px;
	width:200px;
	height:150px;
}
li:nth-child(1) {opacity:0.5;}
li:nth-child(2) {opacity:0.8; }
</style>
<body>
<ul>
  <li><img src="../images/bird.png" alt="鸟" /></li>
  <li><img src="../images/bird.png" alt="鸟" /></li>
 <li><img src="../images/bird.png" alt="鸟" /></li>
</ul>
</body>
</html>
